package cn.adkii.springframework.beans.factory.support;


import cn.adkii.springframework.beans.BeansException;
import cn.adkii.springframework.beans.PropertyValue;
import cn.adkii.springframework.beans.PropertyValues;
import cn.adkii.springframework.beans.factory.*;
import cn.adkii.springframework.beans.factory.config.AutowireCapableBeanFactory;
import cn.adkii.springframework.beans.factory.config.BeanDefinition;
import cn.adkii.springframework.beans.factory.config.BeanPostProcessor;
import cn.adkii.springframework.beans.factory.config.BeanReference;
import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

/**
 * @author malingdi
 * @description
 * @date 2023/11/23 10:40
 */
public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFactory implements AutowireCapableBeanFactory {
    private InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();

    public InstantiationStrategy getInstantiationStrategy() {
        return instantiationStrategy;
    }

    public void setInstantiationStrategy(InstantiationStrategy instantiationStrategy) {
        this.instantiationStrategy = instantiationStrategy;
    }

    @Override
    protected Object createBean(String beanName, BeanDefinition beanDefinition, Object[] args) throws BeansException {
        Object bean = null;
        try{
            bean = createBeanInstance(beanDefinition, beanName, args);
            // 给bean填充属性
            applyPropertyValues(beanName, bean, beanDefinition);
            // 执行Bean的初始化方法和BeanPostProcessor 的前置和后置处理方法
            bean = initializeBean(beanName, bean, beanDefinition);
        }catch (Exception e){
            throw new BeansException("Instantiation of bean failed", e);
        }

        // 注册实现了DisposableBean接口的Bean对象
        registerDisposableBeanIfNecessary(beanName, bean, beanDefinition);

        addSingleton(beanName, bean);
        return bean;
    }

    protected void registerDisposableBeanIfNecessary(String beanName, Object bean, BeanDefinition beanDefinition){
        if (bean instanceof DisposableBean || StrUtil.isNotEmpty(beanDefinition.getDestroyMethodName())){
            registerDisposableBean(beanName, new DisposableBeanAdapter(bean, beanName, beanDefinition));
        }
    }

    private Object initializeBean(String beanName, Object bean, BeanDefinition beanDefinition) {
        // 1. 执行BeanPostProcessor Before处理
        Object wrappedBean = applyBeanPostProcessorsBeforeInitialization(bean, beanName);
        // 执行对象的初始化方法
        try {
            invokeInitMethod(beanName, wrappedBean, beanDefinition);
        }catch (Exception e){
            throw new BeansException("Invocation of init method of bean["  + beanName + "] failed", e);
        }
        // 2. 执行BeanPostProcessor After处理
        wrappedBean = applyBeanPostProcessorsAfterInitialization(bean, beanName);
        return wrappedBean;
    }
    private void invokeInitMethod(String beanName, Object bean, BeanDefinition beanDefinition) throws Exception {
        // 1. 实现接口InitializingBean
        if (bean instanceof InitializingBean){
            ((InitializingBean) bean).afterPropertiesSet();
        }

        // 2. 配置信息 init-method (判断是为了避免二次执行销毁)
        String initMethodName = beanDefinition.getInitMethodName();
        if (StrUtil.isNotEmpty(initMethodName)) {
            Method method = beanDefinition.getBeanClass().getMethod(initMethodName);
            if (null == method){
                throw new BeansException("Could not find an init method named '" + initMethodName + "' on bean with name '" + beanName + "'");
            }
            method.invoke(bean);
        }
    }

    @Override
    public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException {
       Object result = existingBean;
       for (BeanPostProcessor postProcessor : getBeanPostProcessors()){
           Object current = postProcessor.postProcessBeforeInitialization(result, beanName);
           if (null == current) return result;
           result = current;
       }
       return result;
    }

    @Override
    public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException {
        Object result = existingBean;
        for (BeanPostProcessor processor : getBeanPostProcessors()){
            Object current = processor.postProcessAfterInitialization(result, beanName);
            if (null == current) return result;
            result = current;
        }
        return result;
    }

    protected Object createBeanInstance(BeanDefinition beanDefinition, String beanName, Object[] args){
        Constructor constructorToUse = null;
        Class<?> beanClass = beanDefinition.getBeanClass();
        Constructor<?>[] declaredConstructors = beanClass.getDeclaredConstructors();
        for (Constructor ctor: declaredConstructors){
            if (null != args && ctor.getParameterTypes().length == args.length){
                constructorToUse = ctor;
                break;
            }
        }
        return getInstantiationStrategy().instantiate(beanDefinition, beanName, constructorToUse, args);
    }

    /**
     * bean 属性填充
     */
    protected void applyPropertyValues(String beanName, Object bean, BeanDefinition beanDefinition){
        try {
            PropertyValues propertyValues = beanDefinition.getPropertyValues();
            for (PropertyValue propertyValue : propertyValues.getPropertyValues()){
                String name = propertyValue.getName();
                Object value = propertyValue.getValue();
                if (value instanceof BeanReference){
                    // A:依赖B  获取B的实例化
                    BeanReference beanReference = (BeanReference) value;
                    value = getBean(beanReference.getBeanName());
                }
                // 属性填充
                BeanUtil.setFieldValue(bean, name, value);
            }
        }catch (Exception e){
            throw new BeansException("Error setting property values:" + beanName);
        }
    }
}
